Method of making tubs



I July 21, 1942. I R. M. CHESNEY I 2,290,149

METHOD OF MAKING TUBS INVENTOR lfoberf/fl. Chesnex July 21, 1942. R. M. CHESNEY 2,290,149

METHOD OF MAKING TUBS Filed Aug. 1 5, 1941 2 Sheets-Sheet 2 INVENTOR Robe/'1' M- /lesne y Patented July 21, 1942 UNITED STATES ATEN'E' QEFEQ METHOD OF MAKING TUBS Application August 15, 1941, Serial No. 406,992

4 Claims.

This invention relates to the manufacture of tubs and, more particularly, to the manufacture of blanks for tubs composed of sheet steel stamping welded together as disclosed in Rodman Patent No. 2,135,877.

In the manufacture of steel tubs, one of the serious problems is the production of tubs in a range of diiTerent sizes, without involving excessive die cost. Rodman Patent No. 2,114,150 discloses one method of making blanks for tubs of different sizes from one set of die equipment utilizing removable shoes, one for each size of blank to be made. The present invention is an improvement over that of the last-mentioned Rodman patent. As explained therein, in order to make tubs of different lengths by welding bellend blanks of different sizes to identical drainend blanks, it is essential that the depth of all the bell-end blanks at the open end thereof after trimming, be substantially identical to the depth of the drain-end blanks.

According to Rodman Patent No. 2,114,150, this is accomplished by making the bell-end blanks with different bottom slopes so that, despite the diiierence between their lengths, they all have the same depth at their open end. The method disclosed in said patent requires a punch reciprocable through a die ring, and having one of a series of different bottom shoes attached thereto, co-operating with one of a series of pressure pads. I have invented a novel method of making bell-end blanks of different lengths but of the same depth at their open end when trimmed, whereby I avoid the necessity of employing a series of removable shoes on the punch and a separate pressure pad co-operating with each shoe,

In a preferred embodiment and practice of the invention, I use the same punch, pressure pad and die ring to form a series of bell-end blanks varying in length. I obtain the desired identity of the depths of the blanks of the several lengths at their open end by appropriatel controlling the stroke of the punch, which, of course, determines the depth of the resulting blank. I vary the effective lengths of the punch for the different sizes of blanks by securing blocks in a recess in the bottom of the punch. These blocks have a bottom face which slopes downwardly on the same angle as the bottom of the punch and thus form a continuation or extension thereof. I employ a filler block on the pressure pad to bend up the edge of the sheet of stock from which the blank is drawn, at the bottom of the open end of the blank, to limit the flow of metal longitudinally from said end between the punch and pressure pad. The apparatus disclosed herein is claimed in my copending application Serial No. 425,300, filed January 1, 1942, for Apparatus for making tubs, which is a division hereof.

Further details and novel features of the invention will become apparent during the following complete description and explanation which refer to the accompanying drawings, illustrating the preferred embodiment and practice. In the drawings:

Figure 1 is a longitudinal vertical section through the die equipment for drawing bell-end tub blanks of the minimum length;

Figure 2 is a similar view showing the equipment as set up to produce a blank of intermediate length;

Figure 3 is a similar view showing the equipment as set up for drawing a blank of maximum length;

Figure 4 is a diagrammatic View showing the blanks of the several lengths superposed to illustrate the diiference between their lengths and the uniformity of their depths at their open ends.

Figures 5 through 7 are side elevations showing the several sizes of tubs which can be made according to the invention;

Referring now in detail to the drawings, and, for' the present, to Figure l, I preferably employ a double slide press having heads i0 and H operating successively. The head ll carries a punch 12, which is reciprocable through a die ring [3. A blank-holder ring it co-operates with the die ring l3, and is secured to the outer head I 0. The ring I3 is supported on blocks l5 which rest on a foundation It.

The die I3 has an elongated opening therein, the edges of which are rounded as shown, whereby on passage of the punch therethrough a steel sheet I7 is progressively deformed into a bell-end tub blank B. The punch i2 is suitably shaped to produce the desired form of blank, one end of the punch being inclined and rounded as at I 8, and the bottom of the punch sloping downwardly toward the other and as shown at I9.

A pressure pad 20 is carried on a piston 2| reciprocating in a cylinder (not shown) against fluid under pressure. The pad 23 has its upper face sloping downwardly as at 22, and curved slightly transverse to its length to form a matrix adapted to receive the bottom of the tub blank as it is shaped by the bottom of the punch I 2,

A filler block 23 is detachably secured to the pad 20 and co-operates with a hardened plate 24 secured to the punch i2 at the inner end of a notch or recessed portion 25 in the bottom of the punch, to bend up the edge of the sheet H at the bottom of the open end of the blank as indicated at 26. This bent-up portion resists flow of the stock longitudinally between the punch and pad as the latter descend together.

In the operation of the apparatus described above, both the heads and II are initially retracted and a fiat steel sheet of proper size is laid on the die ring IS. The press is then operated to lower the head l0 and the blank holder ring 14. The latter engages the sheet margins and restrains them against excessive flow as the central portion of the sheet is deformed by the punch. After the sheet I! has been gripped by the ring M, the pad is raised by controlling the fluid in the cylinder in which the piston 2| reciprocates. The upward movement of the piston is limited as by a mechanical stop so that the extreme uppermost position of the pad 20 is slightly below the undeformed flat sheet of steel.

The press is next operated to cause the lowering of the head II and the punch l2. The bottom of the punch immediately starts to deform the sheet and the latter is thereby forced into engagement with the pad 20. The edge 26 of the sheet is bent up by the co-action of the block 23 on the pad and the plate 24 on the punch. As

downward movement of the punch and pad continues, the entire body of the blank is shaped properly by drawing that portion of the sheet within the die ring I3, with slight flow of the sheet margins. When the punch I2 reaches the bottom limit of its stroke, it is withdrawn, leav- 2 ing a completed blank which is then removed and trimmed.

The appearance of the blank after trimming is illustrated in Figure 5 where a finished bell-end blank 21 is shown associated with a drain-end blank 28. These blanks are adapted to be formed into a complete tub body by welding them together along the joint 29. To accomplish this welding satisfactorily, it is obviously necessary that the depth of the blanks at their point of abutment be substantially identical. As illustrated in the drawings, the bell-end blank made by the die equipment shown in Figure 1 is that for the shortest tubs, i. e., that shown complete in Figure 5.

When it is desired to make a bell-end blank for a longer tub such as that shown in Figure 6, the equipment already described is modified by moving the filler block 23 to a position indicated at 23' in Figure 2 and by attaching a block to the punch I2 in abutment with the plate 24. The block 30 constitutes a continuation of the punch, its bottom face having the same slope as the bottom of the punch. The equipment as shown in Figure 2 operates in exactly the same manner as described above except that a larger sheet of stock is employed to produce a bell-end blank 3| of intermediate length.

In order that the blank 3| have a depth at its open end the same as that of the bell-end blank 28, so that identical drain-end blanks may be welded to all of the diiferent lengths of bellend blanks, the stroke of the punch I2 is reduced somewhat by appropriate adjustments when drawing bell-end blanks of intermediate length. In other words, the punch l2 and pad 20 do not descend as far when making the blanks 3| as they do when making the blanks 21. The difference between the strokes of the press under the two different conditions is illustrated at 32 in Figure 2. By this arrangement the blank 3|, although it has the same bottom slope as the blank 2'! and is materially longer than the latter, has a depth at its open end precisely the same as that of the blank 21. This is clearly shown in Figure 4.

Similarly, when it is desired to make a bellend blank of still greater length, I replace the block 30 by a block 33, and remove the filler block 23. With this set up, the edge of the steel sheet adjacent the open end of the blank is bent up as at 34 by the co-operation of the block 33 with the die ring IS. The operation of the die equipment shown in Figure 3 is the same as that which has been described above except that the stroke of the press is again decreased slightly, as indicated at 35. The resulting blank 36 is thus shaped to the same bottom slope as the shorter blanks but has the same depth as the latter at its open end. The bottom slopes of the blanks of the various lengths are indicated by the angle a. in Figures 5 through 9, and this angle is the same in all cases. As previously stated, Figure 4 clearly shows that the several sizes of bell-end blanks, though having the same bottom slope but different lengths, have the same depth d at their open ends. The progressive decrease in the stroke of the punch with the increase in the length of the blank means that the depth of the longer blanks adjacent the closed end thereof is somewhat less than that of the shorter blanks, but this difference is rather slight, e. g., approximately A" or less, so this difference is not objectionable.

It will be apparent from the foregoing description and. explanation that by my invention I am able to produce tubs of various lengths by welding to identical drain-end blanks, bell-end blanks of different sizes produced on the same set of die equipment, the only change necessary being the attachment of the blocks 30 or 33 in the case of the two longer blanks and the adjustment of the filler block 23. These parts and the manipulation thereof are quite simple. The blocks 30 and 33 serve merely to increase the effective length of the bottom of the punch whereby it is adapted to work on sheets of longer length. It will be apparent that the bell-end blanks of different sizes produced according to my invention have the same bottom slope, since they are all formed by the same punch and pad, and the blocks 30 and 33 have the same slope on the bottom face as the bottom of the punch. The identity between the depths of the several lengths of blanks at their open ends is obtained simply by controlling the stroke of the punch,

i. e., by reducing the stroke slightly for the blanks of the longer lengths. All the different sizes of blanks are thus suitable after trimming, for welding to identical end blanks to form complete tub bodies in a range of over-all lengths, e. g., 4 feet, 5, and 5 feet.

It will further be apparent that the invention is a marked improvement over the disclosure of Rodman Patent No. 2,114,150 in that removable shoes having different lengths, adapted to be secured to the punch, and different pressure pads, are not required for the several sizes of blanks.

Although I have illustrated and described a preferred embodiment of my invention it will be understood that changes in the procedure and construction of the apparatus may be made without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. In a method of making tubs composed of a sloping-bottom bell-end blank and a drain-end blank welded together, in a range of difierent sizes, the steps including drawing a plurality of bell-blanks of difierent lengths but having the same slope along the bottom thereof, so regulating the depth of the draw for the blanks of different lengths that all said bell-end blanks when trimmed for welding to a drain-end blank, although differing in length, have the same depth at the open end thereof as the drain-end blank, and Welding identical drain-end blanks to said bell-end blanks, thereby producing a plurality of tubs in a range of different sizes.

2. In a method of making tubs composed of a sloping-bottom bell-end blank and a drainend blank welded together, in a range of diiTerent sizes, the steps including drawing a plurality of identical drain-end blanks, drawing a plurality of bell-end blanks of different lengths but having the same slope along the bottom thereof and the same depth at their open ends, and Welding one of said drain-end blanks to each of said bell-end blanks ,thereby producing comblank welded together, in a range of diiierent sizes, the steps including drawing a plurality of sheets of different lengths to form bell-end blanks, drawing the shorter sheets to the same bottom slope as the longer sheets but proportionally deeper than the longer sheets thereby producing blanks of difierent lengths having the same bottom slope and being identical in depth at the open end, and welding to each of said blanks one of a plurality of identical drain-end blanks, thereby producing complete tubs in a range of sizes.

4. In a method of making tubs composed of a sloping-bottom bellend blank and a drain-end blank Welded together, in a range of difierent sizes, the steps including drawing a plurality of bell-end blanks of difierent lengths but having the same slope along the bottom thereof, terminating the draw of the longer blanks at a depth proportionally smaller than the draw of the shorter blanks whereby all the blanks have the same depth at their open end when trimmed for welding to a drain-end blank, and welding identical drain-end blanks to said bell-end blanks, thereby producing a plurality of tubs in a range of different sizes.

ROBERT M. CHESNEY. 

